Method for acoustic leak detection in a district heating network

Abstract

The method is used for acoustic leak detection in a district heating network (3) in which a heat transfer medium is circulated between a combined heat and power plant (1) and consumption points (5). The consumption points (5) have heat meters (10) that operate with ultrasonic flowmeters that can be operated in a leak detection mode for acoustic leak detection. The acoustic signals detected in the leak detection mode are filtered to eliminate extraneous noise, particularly pump noise.

Description

[0001] In drinking water supply networks, it is state-of-the-art to locate leaks acoustically using flow meters installed in the network, e.g., the flowlQ 2200 from the Danish company Kamstrup A / S. Such domestic water meters measure flow using ultrasound, with the ultrasonic receivers used for leak detection and location in conjunction with special software. These ultrasonic flow meters measure leak noises in a range of 1 to 2 kHz when the ultrasonic flow meter is not being used for flow measurement, i.e., when no flow is occurring. Such a method can, in principle, also be used in district heating networks, as described in EP 3 112 823 A1.

[0002] Leak detection and location in district heating networks is a higher priority than in cold water networks, because in the event of a leak, not only water escapes, but also the heat that needs to be transported with the water, resulting in costs many times higher than for a leak in a drinking or domestic water network. In addition, district heating water contains chemical additives, which means that a leak can contaminate the surrounding area.

[0003] However, acoustic leak detection in district heating networks has not yet become widespread because there is practically always flow in a district heating network. Therefore, the acoustic leak detection commonly used in cold water networks, which is performed when no flow is detected, is not feasible in practice. Further complicating the situation is the fact that the pipes in district heating networks are heavily insulated, i.e., they are surrounded by an insulating jacket that significantly dampens the noise generated by a leak.

[0004] Thermography, which involves manually guided cameras or drones, is therefore primarily used to detect leaks in district heating systems. However, this type of leak detection is both complex and only possible where there is a sufficiently clear view of the ground surface above the district heating pipe.

[0005] In addition, electrical methods are used to detect leaks in district heating pipes. The Danish pipe manufacturer Løgstør, for example, builds electrical wires into the pipe insulation, which are electrically connected before the pipes are buried in the ground. Leak detection is then performed using electrical impedance measurement.

[0006] Also state-of-the-art is a monitoring software called "Heat Intelligence," distributed by the Danish company Kamstrup A / S, which works in conjunction with the ultrasonic flow meters installed in the district heating network. This software uses the temperature measurements of the ultrasonic flow meters and detects a leak based on a detected temperature jump.

[0007] Against this background, the object of the invention is to provide an improved method for leak detection in a district heating network.

[0008] This object is achieved according to the invention by a method having the features specified in claim 1. Advantageous embodiments of the method according to the invention are specified in the subclaims, the following description, and the drawing. A heat meter (also called a heat meter or heat quantity meter) for implementing the method according to the invention is specified in claim 15.

[0009] The inventive method for acoustic leak detection in a district heating network, in which a heat transfer medium is circulated between a combined heat and power plant and consumption points, utilizes heat meters provided at the consumption point and operating with ultrasonic flowmeters operable in a leak detection mode for acoustic leak detection. According to the invention, the acoustic signals detected in the leak detection mode are filtered to eliminate extraneous noise, particularly pump noise. The leak detection is performed using ultrasonic flowmeters of a group of heat meters. The measurement is performed in each ultrasonic flowmeter when it detects a flow stop or when a predetermined low flow rate is reached or undershot.

[0010] The basic idea of ​​the method according to the invention is to use the ultrasonic flow meters integrated in heat meters to detect acoustic signals for leak detection and to filter these acoustic signals detected in leak detection mode to eliminate extraneous noise, particularly pump noise. Filtering within the meaning of the invention refers to the partial or complete elimination of extraneous noise, whether by eliminating it from the acoustic signal itself, by eliminating it from the acoustic signal converted into an electrical signal, or by digitizing the converted electrical signals and preparing or further processing them in digital form in such a way that the effect corresponds to filtering.

[0011] In principle, it is advisable to filter out extraneous noise that could interfere with or complicate leak detection in any way. Typically, however, this is the extraneous noise generated by pumps, be they the pumps that circulate the heat transfer medium in the district heating network on the heating plant side or the network side, or the pumps that operate on the consumer side, which circulate the heating medium on the consumer side, both on the primary side and the secondary side, i.e., those separated from the actual district heating network by heat exchangers. This pump noise is transmitted both through the medium being pumped and through the existing piping system, which can be made of plastic and / or metal. In the consumer's house, disruptive noise from pumps, valves, and flow (in adjacent pipes) is transmitted through concrete, walls, or installation boxes, e.g.a housing of a district heating transfer station.

[0012] The leak detection method according to the invention can therefore also be carried out, or in particular, when there is flow in the pipe system. Unlike drinking and service water pipe networks, which only have sporadically flow when water is drawn off at one or more taps, in district heating pipe networks there is almost always a flow due to the nature of the system, since heat transport from the heating plant to the consumer is only guaranteed when there is flow. Thus, even on the consumer side, flow stops in the district heating pipe only occur very rarely during the warmer months. Therefore, if leak detection is to be carried out outside of these special times, a flow is tolerable with the acoustic leak detection according to the invention, but with the elimination of extraneous noise that is disruptive to the leak detection, particularly if this noise emanates from pumps and can be identified and thus filtered out with technically justifiable effort.

[0013] For acoustic leak detection, it is useful to control the group of heat meters in order to not only detect such a leak, but also to be able to locate it and at least define a spatial area where it is present. It may be useful to carry out the leak detection on all ultrasonic flow meters belonging to the specific group of heat meters at the same time, i.e. to control all heat meters belonging to this group simultaneously for leak detection, i.e. synchronized. Simultaneous leak detection with all heat meters belonging to the group is particularly advantageous when the flow has stopped. Such an interruption in flow in a district heating network or a section of such a network only needs to be very brief; times in the millisecond range may be sufficient for acoustic leak detection.Practical tests have shown measurement times of 250 ms, which can easily be achieved by shutting off valves, temporarily shutting off pumps, etc. However, the measurements can also be performed at low flow rates.

[0014] According to the invention, however, this is not absolutely necessary, since according to a development of the method according to the invention the leak detection can also be carried out at a different time, i.e. unsynchronized, by means of ultrasonic flow meters in a group of heat meters, in that the measurement is preferably carried out automatically in each ultrasonic flow meter when either a flow peak or a predetermined low flow rate is reached or undershot. The latter is the case in many areas of the district heating network, at least for a short time. Especially at low flow rates the elimination of extraneous noise is much more effective than at high flow rates. The background noise that is always present in the network is also then significantly reduced. Since the heat meters are always aware of the flow rate or the flow rate thanks to the ultrasonic flow meters they contain.If the sensors have a flow stop, they can essentially trigger themselves to detect leaks as soon as the desired state is reached. Acoustic signal acquisition is then staggered over time, with the data representing the measurement process also receiving a time stamp to enable not only spatial but also temporal assignment of the measurements within a group or, if necessary, across multiple groups.

[0015] Alternatively or additionally, the acoustic leak detection method according to the invention can be used to temporarily block the flow in at least parts of the heat pipe network or on the consumer side. Such a blocking on the consumer side is preferably carried out in the return line to prevent any loss of comfort on the consumer side.

[0016] The acoustic leak detection method according to the invention always aims to distinguish the noise caused by the leak in the pipe network from the ambient noise, i.e. from extraneous noise, in particular pump noise; only then is effective leak detection possible. To support this, an advantageous development of the method according to the invention provides for at least part of the district heating pipe network to be subjected to a pressure that changes over time during the acoustic leak detection, preferably to a predetermined pressure profile. The basic idea here is that the noise caused by the leak is pressure-dependent in both its frequency distribution and its amplitude. Applying a pressure profile thus facilitates the differentiation between leak-related noise and extraneous noise or other flow noise.In particular, acoustic measurements during a high-pressure period of the profile can be compared with acoustic measurements during a lower-pressure period. The specified pressure profile advantageously includes such pressure differences. This also facilitates the identification and filtering of pump noise, since the pressure profile causes a changing pump speed and thus also the frequency of the pump noise. This approach has the particular advantage that district heating remains virtually unaffected, because the leak detection is carried out during the pressure flow; only the pressure profile changes.

[0017] While acoustic leak detection in drinking water or domestic water supply networks detects acoustic signals in the frequency range between 1 and 2 kHz in ultrasonic flow meters in leak detection mode, it has been shown that a much broader acoustic frequency spectrum should be detected when detecting leaks in a district heating supply network. The method according to the invention advantageously covers a frequency range between 10 Hz and 10 kHz. It is understood that, due to this comparatively broader frequency range, filtering out extraneous noise is particularly important. This primarily concerns the extraneous noise emanating from the centrifugal pumps in the supply network.

[0018] The data collected by the heat meters in the leak detection mode of their ultrasonic flow meters is preferably transmitted in the form of data records, preferably wirelessly, to a data collection and processing device (head-end system). Communication with such data collection and processing devices is state-of-the-art for heat meters. In a simple form, the transmission of data packets in one direction may be sufficient; however, bidirectional communication is advantageous, so that, for example, switching to leak detection mode can also be carried out centrally via the data collection and processing device.

[0019] A data collection and processing device within the meaning of the present invention does not have to be a device located at one location; it is conceivable that several spatially distributed data collection and communication devices are provided, which communicate with groups of heat meters and whose data is further processed, for example, in a data center or one or more computers. If such data records from groups of heat meters comprising hundreds or thousands of heat meters are to be evaluated, considerable computing power is required. The evaluation is therefore typically not carried out in real time, but rather when all the data records have been recorded. Especially with battery-powered heat meters, data communication always means additional energy consumption, which should be avoided.Data is therefore only transmitted at specific times, with the channel and signal strength selected to require the lowest possible transmission power. Accordingly, the evaluation of these data sets must be carried out independently of data acquisition.

[0020] As far as extraneous noise generated by pumps in the combined heat and power plant or booster pumps within the district heating network is concerned, it is particularly important to eliminate this noise, as otherwise all of the detected acoustic signals would overlap and complicate leak detection. Therefore, according to a further development of the invention, at least one of these pumps, but preferably the relevant pumps in this area, is specifically controlled to detect the acoustic signals generated during its operation, preferably in the leak detection mode of the ultrasonic flow meter, in order to be able to specifically assign and filter out the signal then detected by the ultrasonic flow meter. Therefore, if one or more heat meters specifically detect such a pump in the leak detection mode, its signal can be identified and filtered out.

[0021] The control is carried out either by the data collection and processing device or, preferably, by an on-site operator using an external control unit, which preferably communicates wirelessly with at least one pump and with at least one ultrasonic flow meter of a heat meter. Such a control unit can be a smartphone with a corresponding app installed on it, which communicates either via the internet or the data collection and processing device with the pump(s) and the ultrasonic flow meter(s), or, if necessary, directly with the heat meters, in order to generate and assign the signals recorded by the ultrasonic flow meters accordingly.

[0022] Eliminating extraneous noise through filtering requires that these noises be identified as extraneous noises, classified, and then eliminated if necessary. In a further development, the method according to the invention therefore requires that acoustic patterns are specifically determined and stored before extraneous noises are detected so that when extraneous noises corresponding to these acoustic patterns are detected, they can be identified and eliminated if necessary. The method according to the invention advantageously distinguishes between extraneous noises coming from the district heating pipeline network and those coming from the consumer, i.e. from the point of consumption. Since extraneous noises coming from the point of consumption are often generated much closer to the heat meter than those coming from the network, it is useful for leak detection in the pipeline network to filter out these extraneous noises coming from the direction of the point of consumption.The method according to the invention thus provides, in a further development of the invention, for detecting the direction of the noise and then, if necessary, eliminating the signals coming from the direction of the consumption point. The direction of an acoustic signal can be determined in a heat meter based on ultrasonic measurement by measuring the amplitude, a speed, or a bevel angle of the signal at two locations and determining the direction from the difference between the two values.

[0023] As explained at the beginning, it is advisable to use as many heat meters as possible for leak detection, especially for leak location, in order to locate a leak by comparing the data sets transmitted by them and, if necessary, to localize it spatially. In this respect, it is advantageous if a number of heat meters are wirelessly switched to leak detection mode by the data collection and processing device for leak detection and then switched back to normal measurement mode after the data has been transmitted. This switchback can also advantageously occur automatically if the relevant data from leak detection mode has been recorded and stored in the heat meter.

[0024] In order to carry out not only leak detection but also leak location using the method according to the invention, it is expedient to either equip the leak location data transmitted by the heat meters with GPS data or to store these in the data collection and processing device in such a way that a spatial determination of the leak location can be carried out according to the GPS data of the transmitted data sets or the GPS data of the heat meters that generate these data sets.

[0025] The method according to the invention is preferably carried out using several groups of heat meters, with each group preferably comprising between 10 and 1000 spatially connected heat meters. It will generally not be practical to use several heat meters with almost identical GPS data for leak detection, as is the case, for example, in multi-family homes. This is generally only useful for leak detection within the building, which can of course be carried out analogously using the method according to the invention. For leak detection in the district heating network, however, it is practical to use only those heat meters that differ sufficiently in terms of their GPS data for leak detection.

[0026] Furthermore, it is useful to determine a background noise for such a group of heat meters that are used for acoustic leak detection in the leak detection mode of their ultrasonic flow meters and to filter this out in the same way for all heat meters in order to free the group of heat meters from this background noise.

[0027] To implement the method according to the invention, a heat meter will have to be adapted accordingly, at least in terms of software. It is particularly advantageous for bidirectional communication with the data collection and processing device if the heat meter has a transmitting and receiving unit for wireless bidirectional communication. Bidirectional communication in the sense of the present invention does not mean communication that confirms the completeness of the transmitted data packets when transmitting data records, but rather communication that encompasses data transmission in both directions, thus in particular also including data with which the heat meter can be controlled for leak detection.

[0028] According to a further development of the invention, it may be expedient to equip the heat meter with a control connection for a shut-off valve or to integrate such a shut-off valve in order to be able to stop the consumption-side flow at least briefly in order to improve the acoustic signal detection.

[0029] Advantageously, the method according to the invention uses noise loggers mounted on the main line side, which transmit acoustic signals to the control center in order to use these acoustic signals together with acoustic signals from the heat meters to eliminate extraneous noise.

[0030] It is also advantageous to carry out the acoustic leak detection during a flow in a pipe, in particular a main pipe or flow pipe.

[0031] Heat meters such as those used to implement the method according to the invention typically have, in addition to an ultrasonic flow meter, two temperature sensors for the supply and return lines. According to a further development of the invention, it is particularly advantageous to equip such a heat meter internally or externally with an acceleration sensor, which can be used to acquire additional data during leak detection, which can also be advantageous for signal determination when filtering out extraneous noise.

[0032] How a leak detection can be designed in practice is shown by the Figure 1 described as an example:

[0033] The basic structure of a district heating network is illustrated by the highly simplified drawing. In a combined heat and power plant 1, a heat transfer medium, typically water, is heated and fed by a pump 2 into a district heating network 3, which has a central flow line 4, which flows into flow lines 4.1 and 4.2, via which consumption points 5 are supplied with heat. From the consumption points 5, corresponding return lines 6.1 and 6.2 lead into a central return line 6 back to the combined heat and power plant 1, where the circuit is closed. All lines 4, 6 have an insulating sheath 7. The consumption points 5 are either directly integrated into the network 3, as was common in the past, or via heat exchangers 8, as is common today. With direct integration, circulation pumps can also be provided within the consumption points 5, which are Figure 1are not shown in detail. When using a heat exchanger 8, at least one circulation pump 9 is provided on the secondary side, i.e., on the side of the consumption point 5, which distributes the heat within the house to where it is needed.

[0034] What all consumption points 5 have in common is that they have a heat meter 10, as is schematically shown for consumption point 5.1 in the bottom right of the drawing. Such a heat meter 10 records the flow rate, i.e. the amount of heat transfer medium flowing through consumption point 5 via supply line 4.2 and return line 6.2. They also have a first temperature sensor T1, which records the temperature in supply line 4.2 as it enters consumption point 5.1, and a second temperature sensor T2, which records the temperature of the heat transfer medium in return line 6.2 as it exits consumption point 5. In addition, heat meter 10 comprises a pressure sensor P1 and an acceleration sensor A1, which records movements / vibrations of the line within heat meter 10.

[0035] The flow rate is recorded in the heat meter 10 by an ultrasonic flowmeter, which measures the speed of the flowing heat carrier using acoustic waves and which has at least one ultrasonic transmitter and one ultrasonic receiver, which are arranged so that the ultrasonic signal permeates the flowing liquid. Typically, two transmitters and two receivers are provided. Heat meters 10 that operate with ultrasonic flowmeters are state of the art and are therefore not described in detail here. Reference is made here only to the heat meters offered under the type designation Multical by the Danish company Kamstrup A / S, which operate according to this principle and which, based on the flow and the temperature difference between the temperature sensors T1 and T2, determine the heat flow from consumption point 5.1 Determine the amount of heat taken, store it and transmit it wirelessly to the so-called head-end system 11, i.e. a data collection and processing device 11.

[0036] In contrast to the prior art, the heat meter 10 has an acceleration sensor A1 which detects the vibrations / movements introduced via the pipeline, as well as a control connection for a shut-off valve V2 arranged in the return line 6.2 and control and communication electronics which make it possible to switch the heat meter 10 into a leak detection mode, to receive acoustic data via the ultrasonic receiver located in the ultrasonic flow meter, to filter it, to time-stamp it and to transmit it wirelessly to the head-end system 11 at the appropriate time.

[0037] In order to filter out disturbing acoustic signals from the consumption point 5.1, the heat meter 10 uses two built-in ultrasonic sensors (not included in the Figure 1 (shown) determines the direction of a signal. Such sensors are spaced apart, e.g., 10 cm. An incoming signal hits one sensor before the other, and this time difference allows the direction to be determined. The signal can then be filtered out if necessary, for example, the signal from leak 15 in heat exchanger 8.

[0038] The heat meters 10 communicate wirelessly with the head-end system 11, which in turn is data-connected to a control center 12, which is also provided on the heating plant side.

[0039] In the Figure 1a leak point 13 in the flow line 4.1 is shown as an example. For leak detection, two groups A and B of heat meters 10 are provided here, which are arranged at different sections of the district heating pipeline network 3. These heat meters 10 can be switched to leak detection mode wirelessly via the head-end system 11 from the control center 12. This can either take place simultaneously or be controlled by the ultrasonic flow meters in the heat meters 10 when a predetermined low flow rate is reached or the flow rate comes to a standstill, e.g. by controlling the shut-off valve V2 in the return line 6.2 of the heat meter 10 of the consumption point 5.1. In principle, this state can also be achieved via a valve V1 from the control center 12 for the return line 6, although this is not possible during normal heating operation.As a rule, leak detection will be carried out when the flow rate is as low as possible and extraneous noise is filtered out, which is typically caused by pumps 2 and 9 shown here as examples.

[0040] Since pump 2 is controlled via the control center 12 of the combined heat and power plant 1, it can be easily integrated into the leak detection process using the heat meters 10. This pressure profile is applied to the district heating network 3 via this pump 2, which is then recorded by the pressure sensors P1 of the heat meters 10 at the consumption points 5. Based on this pressure profile, it is possible to assign the pump noises generated by pump 2 in the network 3. The pump noises can be identified and stored as patterns when they occur during the subsequent measurement process. By filtering out these extraneous noises, leak detection can be carried out even during ongoing operation.

[0041] The groups A and B symbolically represented here, which are arranged at spatially different locations in the district heating network 3, symbolize groups of hundreds to thousands of heat meters 10. As can be seen in the graphic representation, group B, measured in terms of pipe length, is closer to the leak point 13 than group A, so that both when comparing the data within groups A and B and by comparing the data of groups A and B, a certain regional tendency, ideally an almost exact spatial location of the leak point 13, is possible.

[0042] Due to the length of the pipes in the district heating network, so-called "blind spots" occur, i.e. pipe sections where a leak cannot be "heard". Figure 1It may be that heat meter 10 at consumption point 5.1 detects the leak at leak point 13. However, this leak is in the supply line 4.1. This is a large pipe, larger than the house line 4.3, which is often made of a different material, e.g., plastic, and is also located relatively far from the consumer point 5.1. The measured signal will be weak, if detectable at all. To make such a "blind spot" audible, a so-called noise logger 14 can be attached to pipe 4.1. The noise logger 14 is a battery-operated microphone and contains wireless communication electronics. It measures acoustic signals in the main line. Multiple noise loggers can be installed along the length of lines 4.1 and 4.2, and these can communicate either directly with the heat meter 10 or the control center 12.The noise loggers contribute to the detection of extraneous noise and leakage noise by measuring it in a combination process with the heat meters. List of reference symbols

[0043] 1 Heating plant 2 Pump 3 District heating network 4 Supply line 4.1, 4.2 Supply lines 4.3 House line 5 Consumption point 5.1 Consumption point 6 Return line 6.1, 6.2 Return line 7 Insulating jacket 8 Heat exchanger 9 Circulation pump 10 Heat meter 11 Head-end system / data collection and processing device 12 Control center 13 Leak point 14 Noise logger 15 Leak point in heat exchanger T1 Temperature sensor T2 Temperature sensor P1 Pressure sensor A1 Acceleration sensor V1 Central shut-off valve at heating plant 1 V2 Shut-off valve in the return line of consumption point 5.1

Claims

1. Method for acoustic leak detection in a district heating network (3) in which a heat transfer medium is circulated between a heating power station (1) and consumption points (5), wherein consumption points (5) have heat meters (10) which operate with ultrasonic flow meters which can be operated in a leak detection mode for acoustic leak detection, wherein the acoustic signals detected in the leak detection mode are filtered to eliminate extraneous noise, in particular pump noise, wherein the leak detection is carried out by means of ultrasonic flow meters of a group (A, B) of heat meters (10), wherein the measurement is carried out in each ultrasonic flow meter when it has detected a flow stop or a predetermined low flow being reached or undershot.

2. The method according to claim 1, wherein the acoustic signal acquisition is staggered in time, the data representing the measurement process receiving a time stamp.

3. Method according to claim 1 or 2, wherein the measurement is carried out automatically in each ultrasonic flowmeter.

4. Method according to one of the preceding claims, in which, for the purpose of leak detection, the flow is blocked in at least parts of the district heating network or on the consumer side, preferably on the return side.

5. Method according to one of the preceding claims, in which at least part of the district heating network (3) is subjected to a pressure which changes over time, preferably a predetermined pressure profile, during the acoustic leak detection.

6. Method according to one of the preceding claims, wherein the ultrasonic flow meters in leak detection mode detect acoustic signals in the frequency range between 10 Hz and 10 kHz.

7. Method according to one of the preceding claims, in which the data recorded by the heat meters (10) in the leak detection mode of their ultrasonic flow meters are transmitted wirelessly to a data collection and processing device (11).

8. Method according to one of the preceding claims, in which at least one pump (2, 9) is controlled to detect the acoustic signals generated during its operation, preferably in the leak detection mode of the ultrasonic flow meter, the signal detected on the ultrasonic flow meter side being used to filter out this pump noise.

9. Method according to claim 8, wherein, for pump noise determination, data communication takes place between the at least one pump (2, 9), the at least one ultrasonic flow meter and an external, preferably wirelessly connected, control device.

10. Method according to one of the preceding claims, in which extraneous noises are identified on the basis of previously determined acoustic patterns and / or are determined with regard to their direction and eliminated, wherein preferably only the extraneous noises coming from the direction of the point of consumption (5) are eliminated.

11. Method according to one of the preceding claims, in which a number of heat meters (10) for leak detection are wirelessly switched into the leak detection mode by the data collection and processing device (11) and are switched back to the normal measuring mode after transmission of the data or are automatically returned to this.

12. Method according to one of the preceding claims, in which the leak location data transmitted by the heat meters (10) are evaluated in the data collection and processing device (11) taking into account the spatial arrangement of the associated heat meters (11), in particular their GPS data for the spatial determination of the leak point (13).

13. Method according to one of the preceding claims, in which the leak detection is carried out by means of several groups (A, B) of heat meters (10), wherein a group preferably comprises between 10 and 1000 spatially connected heat meters (10).

14. Method according to one of the preceding claims, in which a background noise is determined and filtered out for a group (A, B) of heat meters (10) during the acoustic signal detection for leak detection.

15. Method according to one of the preceding claims, in which noise loggers (14) mounted on the main line side (4.1) transmit acoustic signals to the control center (12) in order to use these acoustic signals together with acoustic signals from the heat meters (10) to eliminate extraneous noise.

16. Method according to one of the preceding claims, in which the acoustic leak detection is carried out during a flow in a line, in particular a main line (4.3) or flow line (4.1, 4.2).

17. Heat meter for carrying out the method according to one of the preceding claims, in which a transmitting and receiving unit is provided for wireless bidirectional communication with a data collecting and processing device (11).

18. Heat meter according to claim 17, in which a control connection for a shut-off valve is provided or which has a shut-off valve, and / or an acceleration sensor (A1) is provided.

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